1. Field of the Invention
The present invention relates to an edge light type backlight unit having a heat sink system which can efficiently emit heat generated by a light emitting element.
2. Description of the Related Art
Generally, a liquid crystal display (LCD) device used in a notebook type computer, a desktop computer, or a mobile communication terminal is a kind of light receiving element and has a backlight unit in addition to a liquid crystal panel. A liquid crystal display (LCD) device, which is a flat panel display device, does not emit the light to form an image by itself. Since an LCD device is a light receiving element which receives light from an outside source to form an image, it requires a backlight unit in addition to a liquid crystal panel. The backlight unit is provided on the rear surface of the LCD device and irradiates the light.
Backlight units can be mainly classified into direct light type backlight units for radiating light from a plurality of light sources provided under the liquid crystal panel, and edge light type backlight units for radiating light from a light source provided on the sidewall of a light guide panel (LGP) to the liquid crystal panel. A cold cathode fluorescent lamp (CCFL) is generally used as an edge light type backlight unit. However, since a CCFL has a low color gamut, it is not suitable for a high-definition and high-resolution TVs or monitors. Recently, light emitting diodes (LEDs) have been used as light sources instead of the CCFLs. For example, a direct light type backlight unit can use an LED emitting Lambertian light as a point light source.
Referring to FIG. 1A, a conventional backlight unit 20 includes LEDs 10 and a light guide panel 15 for guiding the light emitted from the LEDs 10 such that the light is incident on the liquid crystal panel. Referring to FIG. 1B, the LEDs 10 are arranged in a matrix. The LEDs include LEDs for emitting red light, green light and blue light, and the red light, the green light and the blue light are mixed in the light guide panel 15 to produce white light.
LEDs require low power and produce high quality light, but the heat generated by the LEDs adversely affects the brightness and the color temperature of the LEDs.